Nutrient Recovery from Dairy Processing Wastewater Using Biochar

Abstract

In this study, we examined the capacity of magnesium-amended biochar to recover nutrients from dairy processing wastewater (DPW). Our results suggest that biochar engineered with magnesium (Mg–BC) was successful at recovering over 3 mg of PO43−-P per gram of biochar (96%) in synthetic and raw DPW through a combination of adsorption and chemical precipitation. The addition of Mg–BC to increase the pH of the synthetic and raw DPW was likely important in promoting chemical precipitation and increased nutrient recovery. The Mg-dosed biochar also recovered 1.7 mg of NH4+-N per gram of biochar (24%) from raw DPW. However, the raw biochar (R-BC) was only capable of recovering a maximum of 0.5 mg of PO43−-P and an insignificant amount (˂0.1 mg) of NH4+-N per gram of biochar.